In the making of hollow plastic articles, it is common to deliver the plastic in the form of pellets to an extruder which in turn delivers the molten plastic material through one or more cavities. In one type of blow molding, the plastic material is first injected into a neck mold and further extrusion of the material forms a hollow parison integral with the injected neck and thereafter is blown.
Where the material includes colorant, it has been found that in some instances there is a degrading due to the presence of heat sensitive materials. In addition, different color material from a previous run is sometimes difficult to purge from the plastic system.
Accordingly, among the objectives of the present invention are to provide a plastic system which obviates the degradation; which system achieves the result at low cost and with a minimal change to the prior art system.
In accordance with the invention, the plastic system for injection molding and extruding a hollow tube from plastic containing heat sensitive material for thereafter forming into a plastic container by blowing comprising an extruder for melting the plastic and delivering it to an injection system for injecting the plastic into a manifold that delivers the plastic to the tubular cavities of an injection head comprising a static mixer adjacent each of the cavities. By such an arrangement, the plastic flow in each flow channel provides a uniform homogeneous plastic material such that streaks which may be caused by degraded plastic material and previous colors are eliminated.